Role of FIR in limb morphogenesis

FIR 在肢体形态发生中的作用

基本信息

批准号：
8938057
负责人：
Susan Mackem
金额：
$ 6.32万
依托单位：
DIVISION OF BASIC SCIENCES - NCI
依托单位国家：
美国
项目类别：
财政年份：
资助国家：
美国
起止时间：
至
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/8938057
关键词：
Alleles Apical Ectodermal Ridge Apoptosis Biological CCR Cancer Biology Cell Death Cell Proliferation Cell Survival Cell physiology Cells Cessation of life Collaborations Colorectal Cancer Complex Development Developmental Biology Differentiation and Growth Digit structure Drosophila genus Embryo Ensure Erinaceidae FBP interacting repressor Factor Analysis Fibroblast Growth Factor Fingers Fluorescence Gene Expression Regulation Gene Targeting Genes Genetic Genetic Transcription Genomics Goals Growth Homologous Gene Human Intercept Joints Knock-out Lead Learning Length Light Limb Bud Limb Development Limb structure Link LoxP-flanked allele Malignant Neoplasms Mediator of activation protein Mesoderm Mission Modeling Morphogenesis Mus Neoplasm Metastasis Neoplasms Normal tissue morphology Organ Pathology Pathway interactions Pattern Phalanx Phenotype Physiological Processes Play Process Proteomics RNA Splicing Regulation Reporter Research Role Shapes Signal Transduction Skeleton Structure Study models System Systems Biology Tamoxifen Testing Tissues Tumor Biology Vertebrates Wing base beta catenin c-myc Genes cancer therapy cell behavior cell motility cellular targeting design gene function genome wide association study implantation in vivo mutant neoplastic cell null mutation programs promoter recombinase skeletal smoothened signaling pathway transcription factor tumorigenesis

项目摘要

The developing limb is a well studied model for morphogenesis in which many of the regulatory components governing skeletal pattern and growth have been elucidated, providing a strong biological framework for interpreting gene function based on mutant phenotypes. FIR (FBP interacting repressor) is a highly evolutionarily conserved negative regulator of myc transcription present in both vertebrates and Drosophila. The Drosophila homolog (half pint) controls the zone of non-proliferation in the developing embryonic wing disc. The human homolog has been implicated in colorectal cancer; alternatively spliced dominant-interfering forms of FIR are associated with these cancers. Elucidation of the normal function of FIR in mammalian tissues has been hampered by the very early embryonic lethal (prior to implantation) of FIR null mutant embryos, limiting the ability to assess the role of this gene in normal tissue morphogenesis. In collaboration with Dr. Levens (CCR, NCI), who has generated a conditional (floxed) allele of mouse FIR, we are using several Cre drivers to selectively remove FIR from the early limb bud. We want to test whether FIR plays a role in regulating limb outgrowth, and if it does, learn how it acts to regulate growth. In preliminary results, we have found that, surprisingly, loss of FIR function in early limb bud mesoderm results in considerable apoptosis leading to truncations of the limb skeleton. In Drosophila, half pint is a target of Wg (wingless, Wnt) pathway. Interestingly, loss of the Wnt signaling effector, beta-catenin, from limb bud mesoderm also causes limb truncation phenotypes in mouse embryos, related to abnormalities in formation of an early Fgf signaling center in the limb bud (AER, apical ectodermal ridge) that is necessary for limb outgrowth. We are analyzing components of the Wnt pathway to determine whether they are altered in the FIR mutant limbs, along with other analyses of factors and signaling centers critical for cell survival in the early limb. In parallel studies we are analyzing the role of FIR in cell survival and proliferation at the cellular level using conditional mutant derived MEF cells that also carry a conditional tamoxifen-activated Cre recombinase and a floxed-dual fluorescence reporter to allow FACS isolation of recombined (FIR knock-out) cells. These studies will shed new light on the varied roles of FIR in regulating growth, and will have implications for developing cancer therapies that may target function of this Myc-regulator.

发育中的肢体是一个经过深入研究的模型，其中阐明了许多管理骨骼模式和生长的调节组件，为基于突变体表型的基因功能解释基因功能提供了强大的生物学框架。 FIR（FBP相互作用的阻遏物）是脊椎动物和果蝇中存在的MYC转录的高度保守的负调节剂。果蝇同源物（半品脱）控制着发育中的胚胎翼圆盘中的不变区域。人类同源物与大肠癌有关。这些癌症或这些癌症的剪接占主导地位干扰形式与这些癌症有关。早期的胚胎致死性（植入之前）FIR无效突变体胚胎的早期胚胎致死性（植入之前）阐明了哺乳动物组织中FIR功能的正常功能，从而限制了评估该基因在正常组织形态发生中的作用的能力。与莱文斯（CCR，NCI）博士合作，他生成了有条件的（floxed）小鼠FIR的等位基因，我们正在使用几个CRE驱动程序从早期的肢体芽中选择性地删除FIR。我们想测试FIR在调节肢体生长中是否起作用，如果确实如此，请学习如何调节增长。在初步结果中，我们发现，令人惊讶的是，早期肢体中胚层中FIR功能的损失导致大量凋亡导致肢体骨骼的截断。在果蝇中，半品脱是WG（无翼，Wnt）途径的目标。有趣的是，肢体中胚层中Wnt信号传导效应子β-catenin的丧失还会导致小鼠胚胎中的肢体截断表型，与形成早期FGF信号中心的异常相关的肢体芽（AER，尖端，外胚层脊）中的异常是肢体的必要。我们正在分析Wnt途径的组件，以确定它们是否在FIR突变体的四肢中发生了变化，以及其他因素和信号传导中心的分析对于早期肢体中细胞存活至关重要。在平行研究中，我们使用条件突变体的MEF细胞分析了FIR在细胞水平的细胞存活和增殖中的作用，这些突变体还携带有条件的他莫昔芬激活的CRE重组酶和floxed Dual Dual Fluorescence Reporter允许面部分离重新组合（FIR敲除）细胞。这些研究将为FIR在调节生长中的各种作用提供新的启示，并将对可能针对该MYC调节剂功能的癌症疗法产生影响。